1. Field of the Invention
The present invention relates to an apparatus and method for measuring a dielectric constant, and more particularly, to an apparatus and method for measuring a dielectric constant by inserting a sample into a cavity resonator.
2. Discussion of Related Art
With the acceleration in the developmental progression of various microwave devices, it is necessary to measure a dielectric constant that is an electrical property of a material more accurately and reliably in the microwave band.
In addition, a problem with a material production process may cause a problem with the uniformity of the dielectric constant of the material, and thus a test for the uniformity of the dielectric constant of a material is also needed.
A method of measuring a dielectric constant using a cavity resonator is widely used.
A cavity resonator is in the form of a conductor surrounding a cavity, and is used in a wavemeter, a filter, measurement of a permittivity or a permeability in the microwave band, etc. using the resonance of the cavity.
In particular, a method of measuring the permittivity and permeability of a material in the microwave band using a cavity resonator is referred to as a cavity perturbation method.
In the cavity perturbation method, a sample to be measured is inserted into a resonator, and its permittivity and permeability are measured from a resonant frequency shift and the variance of a quality factor before and after the insertion of the sample.
Such a cavity perturbation method involves inducing a very little perturbation in the cavity resonator, and thus a dielectric to be measured should be processed to have a diameter of about 2Φ in X-band(8˜12.5 GHz).
In addition, when the diameter of an insertion hole is formed to be large to insert a dielectric into a cavity resonator without processing the dielectric, an electromagnetic signal leaks through the insertion hole.